Domestic appliance



Feb. 18, .1958 c. A. STICKEL DOMESTIC APPLIANCE Filed Dec. ,27, 1955 mmvron.

Carl A. Sfic/re/ BY Fig. 2

His Afro/nay United States Patent-O DOMESTIC APPLIANCE Carl A. Stickel, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 27, 1955, Serial No. 555,335

9 Claims. (Cl. 219-37) This invention relates to a domestic appliance and more particularly, to the fold back type of surface heater.

Recently, surface heaters have been sold for installation upon the back portion of kitchen base cabinets. These heaters fold back upwardly against a wall at the rear when not in use and fold down forwardly for active use. Although the wall at the rear is made of stainless steel and ventilated, it has been found that this was discolored whenever heaters were folded back when hot. This discoloration evoked numerous customer complaints.

It is an object of this invention to automatically prevent the folding back of this type of surface heater whenever the surface heater is hot to prevent damage to the wall structure but permit the folding back whenever the surface heater has cooled sufliciently.

These and other objects are attained in the form shown in the drawings in which a box-shaped metal structure containing a surface heater is hinged at its rear or lower edge to the bottom of a hollow ventilated wall structure. This wall structure is provided with an upstanding projection adjacent the hinge to form a keeper while the box-shaped structure supporting the surface heater unit is provided with a movable strip. This strip may be made of bimetal itself or it may be of aluminum to combine with the stainless steel metal top to form a bimetal actuating arrangement. These strips derive sufficient heat from the surface heater to bow downwardly when hot to interengage with the keeper to prevent the folding back of the unit when the surface heater is hot.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a plan view of a fold back surface heater unit embodying one form of my invention;

Figure 2 is a fragmentary vertical sectional view taken along the line 22 of Figure 1 showing the location of the movable strip when the heater is hot; and

Figure 3 is a somewhat similar but more fragmentary view similar to Figure 2 but showing the location of the movable strip when the surface heater is cool.

Referring now to the drawings and more particularly to Figures 1 and 2 there is shown an upwardly extending wall structure 20 adapted to be supported by the top surface 22 of a kitchen base cabinet. This wall structure includes a bottom wall 24 resting directly upon the surface 22, a back wall 26 and an abbreviated downwardly extending front wall 28 forming the ventilating flue 30. The top of the front wall 28 is provided with outlets 32 for the ventilating flue 30. At the front of the bottom wall 24 there is provided a short upwardly extending wall 34 provided with a hinge pin 36 to wh ch is connected the hinge member 38.

2,824,205 Patented Feb. 18, 1958 ice The hinge member- 38'is connected directly to the rear. structural member 40 of a fold back appliance 42. This fold back appliance42 also includes a box-shaped sheet metal structure 44 of stainless steel having its. opening in the top wall. This opening receives a sheathed tubular type of surface heater 46. The heater 46 has a tangential extension connecting with an electrical terminal 48. The electrical terminal 48 is connected by flexible conductors to a suitable power source. The tangential extension of the surface heater 48 is rotatably mounted in the bearing 50 which is structural: ly. connected to the top wall of the box shaped struc-. ture 44. The box shaped structure 44 also includes bottom, frontand side walls as well as a suitable drip pan 52 directly beneath the surface heater 46. The bottom wallof the structure 44 is provided with a spacer 5.4 at the rear and a combined handle and spacer 56v at the front. At the rear portion of the top wall of the box shaped structure is an upwardly curved shield 58. which extends upwardly into the bottom of the flue 30. By this arrangement the front and rear spacers 54 and 56 space the bottom wall of the unit 42 sufficiently away from thetop surface 22 to prevent scorching thereof during the operation of the surface heater 46.

If the. unit 42 is folded back against the wall structure 20 when the surface heater is hot, the heat is apt to discolor parts of the, wall structure 20 adjacent the heater 44;even though the wall structure 20 is ventilated. Particularly, theportions 28 and 32 are apt to be discolored as well as the top surface. Even though ade' quate instruction is given directing that the unit 42 be not folded baclcwhilev the heater is hot, this is apt to happen occasionally through forgetfulness. To prevent this occurence I provide a keeper 58 extending upwardly from the strip 34 to a position immediately beneath the top wall of. the box shaped structure 44 as particularly shown in Figure 2. This keeper 58 coopcrates with a bimetal construction in the form of an aluminum strip 60 directly beneath the rear portion of the top wall of the box shaped structure 44 and immediately in front of the keeper 58 as shown in Figures 2 and 3'. The ends of this strip 60 are spot welded or otherwise fastened to the bottom inner surface of the top wall of the structure 44 as indicated by the small xs in Figure 1.

Also, as best shown in Figure 1, there is provided a forward and inwardly extending extension 62 which extends into contact with the tangential portion of the surface. heater 46 immediately in front of the pivotal bearing support 50 as shown in Figures 2 and 3. The strip 60 will thus receive heat from the surface heater 46 in several different ways. The extension 62 of the aluminum strip will conduct heat from the heater 46 by direct conduction to the aluminum strip 60. Also some heat will be conducted thereto through the stainless steel box shaped enclosure 44. Some heat will be carried by convection within the unit also. The stainless steel adjacent the strip 60 will remain comparatively cool because of its poor conductivity and because it is ventilated and also exposed to the ambient air. The aluminum strip 60 will be much warmer. minum expands at a much more rapid rate than stainless steel and has a much higher coefficient of linear eX- pansion.

The effect of this difference in coefficients of expansion and also the difference in the temperature of the aluminum strip and the stainless steel augment each other to cause the center portion of the strip 60 to bow down as indicated in Figure 2. When so bowed down the strip 60 willlatch or, catch upon the keeper 5S and thereforewill not pass the keeper. This arrangement. there- Also, alu-' fore constitutes a form of latch preventing the unit 42 from being lifted up and folded back against the wall structure 29. Instead of aluminum and stainless steel other combinations of metals may be used if desired with the strip 60 being of the higher expansion metal. For example, an Invar metal could be used for the box shaped structure 44 and copper for the strip so. Also instead of aluminum or copper the strip 6i}: and its extension 62 may be made of some form of bimetal with the high expansion side facing downwardly. When heated, such a bimetal strip will also bow downwardly in the same manner as the strip 60 if made out of aluminum and will interengage with the keeper 58 to form a latch preventing the lifting of the surface heater unit 42. When the surface heater 46 and the unit 42 have been allowed to cool sufficiently, the strip 6t) will return to its fiat position against the under side of the top portion of the box shaped enclosure 44 to the position shown in Figure 3. In this position, the strip 60 will be disengaged from the keeper clear the top of the keeper 53 when the unit 42 is lifted. In this way when the surface heater unit 46 has cooled the unit 42 can be lifted to its upwardly extending position against the wall structure 2%.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow,

What is claimed is as follows:

1. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, and a thermally controlled stop means cooperating with said unit and support to prevent the return of said unit to its upwardly extending position adjacent said support as long as said surface heater is hot.

2. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, and a thermally controlled stop means including movable interengaging means between said unit and support and thermal operating means for said interengaging means responsive to the temperature of said surface heater to prevent the return of said surface heater to its upwardly extending position adjacent said support as long as said surface heater is hot.

3. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, and a bimetal latch means responsive to the temperature of said surface heater for preventing the return of said unit to its upwardly extending position as long as said surface heater is hot.

4. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, a keeper connected to said support, said unit being provided with a thermally operable latch responsive to the temperature of said surface heater and effective when said unit is in, its forward position on said work surface for engaging said keeper to prevent the return of said unit to its upwardly extending position as long as said surface heater is hot.

5. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and'having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, a keeper connected to said support, said unit being provided with a bimetal construction having a portion extending into contact with said heater and a second portion movable when hot into a position engaging said keeper to prevent the return of said unit to its upwardly extending position as long as said surface heater is hot.

6. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, of the sheathed tubular type, a keeper connected to said support, the top of said unit being formed of metal, a bimetal strip fastened to said metal top and located and arranged to move when heated into interengaging relationship with said keeper to prevent the return of said unit into its upwardly extending position as long as said heater is hot.

7. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support'to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, of the sheathed tubular type, a keeper connected to said support, the top of said unit being formed of metal, a bimetal strip fastened to said metal top and'located and arranged to move when heated into interengaging relationship with said keeper to prevent the return of said unit into its upwardly extending position as long as said heater is hot, said bimetal strip having an extension extending into contact with said surface heater to receive heat from the surface heater. I

8. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being provided with a surface heater, of the sheathed tubular type, a keeper connected to said support, the top of said unit being formed of metal having a low coefiicient of linear thermal expansion, a strip having a substantially higher coefficient of linear thermal expansion fastened at 'two end portions to said top so arranged that upon heating its intervening portion will bow away from said top into interengaging relationship with said keeper to prevent the return of said unit into its upwardly extending position as long as said heater is hot.

9. A kitchen appliance including an upwardly extending support adapted to be associated with a work surface and to extend upwardly therefrom, a unit normally extending upwardly in front of and directly adjacent said support and having a lower pivotal connection with said support to allow the unit to pivot forwardly onto said work surface, said unit being providedwith a surface heater, of the sheathed tubular type, a keeper connected to said support, the top of said unit being formed of metal having a low coefficient of linear thermal expansion, 8.

strip having a substantially higher coefiicient of linear thermal expansion fastened at two end portions to said top so arranged that upon heating its intervening portion will bow away from said top into interengaging relationship with said keeper to prevent the return of said unit into its upwardly extending portion as long as said heater is hot, said strip having an extension extending into contact with said surface heater to receive heat from the surface heater.

References Cited in the file of this patent UNITED STATES PATENTS Gomersall Dec. 21, 1943 Pellegrin Nov. 11, 1955 Sandin Mar. 13, 1956 Howell June 12, 1956 

